Imlac PDS-1D Simulator progress

From: Tom Uban <>
Date: Thu Feb 24 22:14:15 2005

Hello all,

I had been talking about writing an Imlac PDS-1D simulator for some time
and had not quite decided what platform to write if for, etc. I finally
made some decisions (sorry it's my first windows application) and got busy.

I've made great progress since starting the program last Saturday evening.
The windows interface is fairly well roughed in and has a display window
with some test lines floating around on it, a programmer's console window
with a picture of the console painted in it, a debug output window which
has the machine state scroll by as the primary CPU executes, a memory dump
window which you can scroll to see the memory location of interest, and
finally a tutorial window which you can scroll to see a tutorial on how
the Imlac/simulator functions, etc.

I also have some menu options which allow you to load a program to the Imlac's
simulated TTY port, start the CPU, stop the CPU, single step the CPU, set a
breakpoint, clear a breakpoint, and bring up the memory window.

The state of the program as of tonight is that the main CPU executes the
simulated diode ROM TTY bootstrap loader which reads in a program that
incorporates the secondary TTY bootstrap loader on the front, just the
way that the original Imlac works. It then auto jumps to the secondary
loader which then reads in the actual program at the location specified
in the image. Finally, it auto jumps to the program (depending on the
way that the image is setup), which in this case is a simple program to
put the word hello in the center of the display. This all runs perfectly!

My next step is to code the display list processor so that I can actually
see what the program is putting onto the display...

Once I have the program in a more (or less) fully functional state, I will
make an executable available so that anyone interested can help find the
bugs and make suggestions.

Received on Thu Feb 24 2005 - 22:14:15 GMT

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